Old School Crunch Amp - CR100

Over the years, brand names are sometimes passed along from one owner to another. Remember Polaroid instant cameras? It was only a few years ago when you may have noticed DVD players branded with the Polaroid name. Well, unfortunately in most cases, the same passing along of name brands happens in the car audio world. I myself, dropped out of the car audio industry for nearly 10 years and when I returned, the brands I knew once as high quality, "Made in the USA" were well....not what they used to be. Some people may argue the Internet forced many car audio companies out of business and although I'm not sure it is 100% the case, I'm sure it had an affect on the industry.

Now, why must I bore you with history of car audio brand names? Well, because the next amplifier I'm going to talk about is the Crunch CR100 from approx. 1992. This amp was one of several made by Zed Audio, regarded by many as some of the better old school amps. Other brands, such as HiFonics and Autotek (among others), had models of amplifiers made by Zed Audio. If you happen to visit or search eBay, you'll notice the Zed-built amps usually go for a premium.

Unlike most modern car audio amps, the CR100 has a harness for speaker connections. I'm not sure why companies continued to use these harnesses instead of barrier strips into the mid 90's?. As most of you know, these harnesses are usually lost over the years or have been cut so many times, the wires are too short! Luckily, the Crunch CR100 I picked up had about 8 inches of speaker wire and even more power/ground wiring length. An immediate problem I had was identifying the speaker and remote turn on wiring colors. Some old school amps used red for remote turn on, others used blue...this amp has both! I opened the amp to reveal the guts and it appeared the blue was the turn on, however I wanted to be 100% sure, so I confided in one of my favorite resources - diymobileaudio.com. Within a few minutes, a member posted the wiring diagram and even a link to the owner's manual. Wow, this is great!

Zed Built Crunch CR100 Guts

The CR100 also allows plug-in modules for crossover/EQ and the one on this particular unit has an M30 module - selectable high/low pass crossover, adjustable frequency and bass boost at 45hz. At the time this amp was new to the market, Crunch offered several different modules so you could customize the amp to your liking.

Crunch CR100 with M30 Module

Now that I have the wiring guide, let's hook this baby up and see what she'll do! Since I was unsure if the amp would handle realistic 1ohm loads, I kept my testing loads to 2ohms minimum (2ohms stereo or 4ohms bridged mono). I connected up the amp to my Audio Authority 100A 13.8v power supply to guarantee I had plenty of juice for the test. The manual suggests a 15A fuse, yet strangely enough says it will consume 14A at full power into 4ohms...what about 2ohms? 15A sounds a little small to me. This amp just has to be more powerful than a Rockford Fosgate Punch 45HD....doesn't it?

Crunch CR100 Wiring Harness

If you read some of the enthusiast forums online, you'll hear rhetoric like "extremely underrated" and "highly underrated" when referring to these old school amps. As my test have shown, in some cases this is accurate, but in most cases the old school amps are only slightly underrated.

Here are the ratings obtained from the Owner's Manual:

• 50w/ch @ 4ohms stereo
• 90w/ch @ 2ohms stereo
• 180w bridged @ 4ohms

And here are the official OldSchoolStereo.com test results for the Crunch CR100:

• 61.93w/ch @ 4ohms stereo
• 88.84w/ch @ 2ohms stereo
• 198.8w bridged @ 4ohms

For additional information on my testing methods, see my previous post: Testing Output Power from Old School Amps. 

In addition to the power output tests, I hooked up the amp to a few speakers including a JL Audio 8W1 and a 12" Rockford Fosgate Punch classic sub. I set the CR100's M30 module to low pass at approx. 120Hz. The Crunch CR100 delivered all the power the JL 8W1 wanted and kept great control of the sub during testing. I demo'd several songs including; Jazz, Pop, Rock and Rap samples from my BigD demo CD. The nearly 200 watts at 4ohms mono was ample power to shake items on the wall of the OldSchoolStereo labs (aka "my garage"). Not only impressive from a 200 watt amp, but also from a 8" subwoofer!

The Rockford Fosgate PCH-812 subwoofer is 8 ohms, so it was only seeing around 100 watts. It is a mid-90's subwoofer and only needs 100-200 watts for ample output. Again, the Crunch CR100 provided clean, accurate power allowing the Punch sub to stand up to it's name!

I'm not sure how good the Crunch CR100 would prove pushing late model, heavy magnet, inefficient subwoofers...but it does a great job powering similar age (mid 90's) subwoofers and would be a great amp for a modest system. I guess one day I'll have to get some newer subwoofers to use testing these old school amps. Yep, I'll do that just as soon as the donations help pay for some...

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Update: 6/26/11


I just located some Crunch amplifier ads from 1992 and 1993 Auto Sound & Security magazines. These ads show off the CR series amps and plug-in modules. With this information, I updated the post to note the amps were from the 1992 timeframe (not 1994) as originally stated. See a couple of the ads below:

Crunch Amp Ad from May 1993 - Auto Sound & Security

Crunch Amp Ad - November 1992 - Auto Sound & Security

A Rare 1982 Rockford Fosgate Amplifier - Punch Power 360

My earliest recollections of aftermarket car audio amplifiers was the mid to late 1980's. Rockford Fosgate, along with a few others (Orion, Precision Power, Soundstream, etc) ruled the car audio aftermarket at this time. But, what about the early 80's? I know companies like A/D/S and Nakamichi were around, but why would manufacturers produce high output car audio amplifiers when 6x9's were high tech at the time? 

Well, if you know the culture of Rockford Fosgate, then you know why they produced an amp like the Punch Power 360 back in 1982. This amp was rated at 90 watts x 4 channels into 4ohm loads and although bridgeable, was not designed for loads less than 4ohms in stereo and 8ohms in mono. The Power 360 retailed for around $900 and from the research I've done, less than 50 were produced. Can you imagine the market for a $900 car audio amplifier back in 1982? All assembled and soldered by hand in the Rockford headquarters in Arizona. Unlike later Rockford amps, the Power 360 used bi-polar output devices as opposed to mosfet. You'll notice in later amps (late 80's - early 90's), Rockford is VERY proud of the mosfet outputs as nearly every amp has "Mosfet" listed in it's title.

Now, nearly 30 years later, what's the chance I'd come across a 1982 Punch Power 360 amplifier in ANY condition, much less near mint? Well, I wouldn't have placed any bets on it, that's for sure! I've seen a few on eBay over the years, a few from serious collectors, but unlike a Punch 45 or 150, this is an amp you just don't see very often. Not only was I fortunate enough to acquire this rare beast, I was also given some literature from another Rockford Fosgate collector.

1982 Rockford Fosgate Punch Power 360 Literature

And the "Pre-Z" pre-amps that matched up with the Power 360:

1982 Rockford Fosgate Punch Power 360 Pre-Amps - 250, Z & ZX

Now, on to the actual amp I picked up as I'm sure you are intrigued, right? I'm sure there are some people with their $100 2000-watt amps, who don't really get the excitement here....I can understand as old school and vintage stereo equipment is not everyone's cup of tea. However, this is Old School Stereo, so I'm not too concerned, as my audience should enjoy the vintage gear.

First up is a top picture of the Rockford Fosgate Punch Power 360's heat sink. Notice the "Rockford Fosgate" emblem on the amp plate. Other 360's I've seen up for sale were missing this cosmetic piece. Also, this amp is not missing a fan shroud...the Punch Power 360 and bipolar Power 650 amplifiers did not come equipped with a fan shroud.

1982 Rockford Fosgate Punch Power 360 Top View

Next up is the bottom of the amp. As with most of the Power series models, there is quite a bit of information silk-screened on the bottom of the amp. Some of this information includes wiring color codes for speakers, DIN connector and power wires. There is also access to the gain controls for each left and right channel from the "high" and "low" channels (most amps would denote these channels as "front" and "rear"). See more details below:

1982 Rockford Fosgate Punch Power 360 bottom view

Although this amp was introduced in 1982, it still had a full 2-way active crossover built-in. The "high" channels could be set either "flat" or at selectable frequencies with a 12dB/octave high-pass slope. The "low" channels offered the same crossover slope for low pass signals. Although the amp was designed to work with line-level inputs, the "high" channels were only accessible if the DIN connector was used. You could use RCA inputs only for the low channels. I'm guessing Rockford thought if you could afford a $900 amp back in 1982, you could also drop a few more hundred on a "Pre-Z" pre-amp (see pictures from literature). Luckily, these days, we have DIN to RCA adapters, so you don't have to own one of the super rare Pre-Z pre-amps to utilize the high channels of this amp.

Rockford Fosgate Punch Power 360 Speaker Harness and Inputs

Keep watching for an upcoming bench test of this amplifier where I'll give actual output power results. Also, if anyone has any additional information on this amp or has any corrections to what I believe are facts above, please contact me oldschoolstereo at gmail.

-BigD

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MASSIVE Old School Car Audio Picture Gallery

To all of the old school fans who haven't seen this, get your coffee and a comfortable chair and enjoy going through 10,000 old school car audio pics!

Old School Audio's Picasa Gallery

Wow, what a collection! Great work by the guy who set this up. Enjoy the trip down memory lane.

-BigD

Old School Car Audio Literature Wanted!

In addition to the Car Audio Magazines, I'm also searching for some Old School Car Audio literature, brochures and other training manuals. I'm particularly interested in Rockford Fosgate (1984-1995) literature and especially some of the RTTI training manuals. I'm also looking for Orion, PPI and Phoenix Gold literature up to 1995.

I've posted some of the Rockford literature I've been able to find over at the Rockford Fosgate Vintage Forum. Let me know what you have. I'd also be interested in copies if you want to keep the originals. Remember, oldschoolstereo.com is only a hobby currently and I've already spent a ton outfitting my test bench so I could measure amplifiers actual output power...

Contact me at oldschoolstereo at gmail or via comment below if you have anything to offer up. Thanks!

-BigD

Old School US Amps 50HCA vs. USA-50

I recently put a couple of US Amps amplifiers (1992'ish US-50HCA and 1999'ish USA-50) on the OldSchoolStereo.com test bench. The outcome was not quite what I expected. Both amplifiers are rated at 25 watts x 2 into 4ohms.

First up is the 1992'ish US-50HCA, which is finished in a beautiful blue color and is in AMAZING condition to be a nearly 20 year old amp. As with most of the late 80's and early 90's car amplifiers, the 50HCA has direct wiring, no terminal strips for the wiring connections. The 50HCA requires a 30A fuse and is stable to 1ohm mono or 0.5ohms stereo, according to the manual. Later models of this amp, known as the USA-50HC, require a 75A fuse, and are likely to be MUCH more underrated than this model. US Amps denoted their "competition" amps as either HCA,  HC or VLX series.

Proceed forward a few years to approximately 1999 and you could pick up a US Amps USA-50 in your choice of several colors. My sample is purple in color and has terminal strip connections for speakers and power. It also has a clear acrylic cover on the bottom of the amp to show off the "guts". The standard USA model amplifiers were rated for 1ohm stability in contrast to the HCA, HC or VLX series' 0.5ohm stability. The USA-50 requires a 25A fuse and also includes a 100Hz high pass or low pass crossover.

I was expecting the US-50HCA to be a beast, but not so much. Here are the results (RMS unless otherwise stated):

4ohms stereo - 33.4w/ch
2ohms stereo - 59.6w/ch
4ohms bridged - 126.3w
2ohms bridged - 198.2w
Max Output at 2ohms mono - 282.5w (hard clipping)

(The US-50HCA, like the Orion 225HCCA is rated to handle 1ohm mono and 0.5ohms stereo and I don't have the resistor bank loads to test these configurations yet.)

And the USA-50:

4ohms stereo - 38w/ch
2ohms stereo - 65w/ch
4ohms bridged - 133.7w
2ohms bridged - 167.6w
Max Output at 2ohms mono - 274.9w (hard clipping)

Surprised with the test results? I was. I guess the real test will be the 1 ohm mono test for the US-50HCA to see how much power it's really capable of. Now, let's see if I can sell a few amps to fund the needed resistors for the additional 800W 2ohm load.

Stay tuned, more coming soon...



See both amps pictured below; 50HCA in blue and USA-50 in purple...

US Amps US-50HCA on top and USA-50 on bottom

US Amps US-50HCA on top and USA-50 on bottom

US Amps US-50HCA Guts

Testing Power Output from Old School Amps - Part 2 - Video Demo

I recently did a video review showing the details on how I measure output power on my old school amps. I've had a ton of questions with people wanting me to explain further the process. If you want to do this yourself, you'll most likely need to invest some money in the tools. At a minimum, you'll need the following:

• 12v Automotive starter or Marine Deep Cycle battery or 12-14.4v Power Supply with enough output to handle your amp's load
• True RMS Volt Meter
• Oscilloscope (My Velleman HPS-50 has a built-in RMS Volt Meter)
• Speakers or Resistors for "loading" the amp

Watch the video to see the components I use for my tests. 


Click the link if you prefer to see the video in HD (720 or 1080p):

Old School Amp Output Test Demo in 1080p HD!

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More 90's Cheater Amps Coming Soon...

What's up old school fans? Sorry, it's been too long since my last post. I have acquired a few more "cheater" amps from the 90's I'll be testing soon. I've decided to stick with the "50 watt" (25x2) cheater amps as these are more affordable and easier to come by.

Here's a 1992'ish US-Amps US-50HCA, high-current, competition 25x2 amp:

US Amps US-50HCA - 1992 Model in 9.5/10 Condition

Another popular 25x2 cheater amp from the 90's was the HiFonics Ulysses. This mode is the Ulysses VIII, which has the Utilink connectors for speaker and power. Unfortunately, my amp was missing these connectors and since Zed stated these connectors are no longer made (the power connectors were specifically tooled for these amps and no longer manufactured). The speaker connectors are easier to come by. You can either spend $15-20US on eBay or search the Digi-Key catalog for a suitable replacement. I chose the latter.

Fully Polished 1996 HiFonics Ulysses VIII

More details on these cheater amps and maybe I'll be able to come across a few more to include in my shootout. I'm looking for 1) MTX 225HO 2) MTX MTA 225 (clone to the PPI Pro Mos 25) 3) Autotek 9050BTS and a few more I can't think of right now.


Here is the list of 90's cheater amps thus far for my shootout:

1) Rockford Fosgate Punch 45HD
2) Precision Power Pro Mos 25
3) Phoenix Gold MPS-2240
4) Orion 225HCCA (Gen2 and Gen3)

5) US Amps US-50HCA

6) HiFonics Ulysses VIII

So, how will I perform the shootout? Well, I'm thinking a true power output test using my dummy loads and oscilloscope as the first test. I plan to have the means of testing loads from 4ohms down to 1/2 ohm. Obviously, I'm not going to load amps, such as the Punch 45HD lower than 1ohm as it was not intended to handle extremely low impedance loads as some of the others were. Many people may argue the Punch 45HD should not even be considered as a cheater amp, but those people can do their own shootouts!

In addition to the power output tests, I'll also demo each amp powering one or more subwoofers. It will be interesting to see if the most powerful amp also controls the subwoofer(s) best. We'll find out soon enough...

-BigD

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Update: 6/27/11

Many of you have contacted me asking why am I taking so long to post the shootout between the cheater amps I have listed above. Honestly, I was hoping to get the HiFonics Ulysses VIII amps repaired as they were both dead. My repair tech said it would be about $100/ea to have them fixed and since I needed some other amps repaired, I decided to trade in the Ulysses amps. That said, I won't be getting them back, so I'll have to remove them from the test. I've seen a few Autotek 9050BTS's lately, so maybe I'll be able to pick up one of those for the shootout.


In addition, the Phoenix Gold MPS-2240 is experiencing the same issue as many 90's Phoenix Gold amps....leaky output capacitors. These capacitors will need to be swapped prior to any further testing with this amp. Too bad as it may be several months before I'm able to get around to having it repaired. 


Stay tuned for updates....

Old School Cheater Amps - RMS Power Output Test Results

I'm sure many of you have been eager to see my test results from my previous posting on early 90's "cheater amps". Well, I've finally assembled the pieces needed to test RMS power output from the amps. See my previous post for details on my testing methods.

Did I have any favorites? I must say, I thought the Orion 225HCCA would take top honors, but envisioned the Phoenix Gold MPS-2240 would be close behind. Although the Rockford Fosgate Punch 40i DSM was not included in my original "cheater amps" posting or the video I created, I felt it was a worthy opponent to the similar amp models. I put together a separate video on the Punch 40i DSM a while back and it nearly blew me away with it's power and clarity....I guess I was unaware of just how underrated this little amp is!

The Precision Power Pro Mos 25 was no slouch either. It wouldn't win the price/performance ratio, but it outputted 1.5x or greater it's rated output at all test loads. Since this is not a sound quality test, the only comparisons were RMS output power. The PPI Pro Mos 25 would probably gain points to some people for it's "Art" design, but I was always a bigger fan of the black series PPI amps. Also, in the old school, lacking bass and/or treble controls would be another minus for me.

The venerable Punch 45HD was a favorite back in the early 90's and for good reasons. It was reasonably priced ($279 US) and put out at least 2x it's rated power at 2 and 4 ohms. As I've stated in the past, Rockford didn't rate this amp to handle 1 ohm stereo or 2 ohm mono loads; however I've had a Punch 45HD since December 1991 and used it for several years in the 2 ohm mono configuration with no issues whatsoever. It was interesting to see the power output lower in the 2 ohm mono test than the 4 ohm mono test with the Punch 45HD. The limiting circuitry must have come into play to protect the amp from overload.

The Orion 225HCCA and Phoenix Gold MPS-2240 were the only two amps in my test rated to handle 1 ohm mono or 0.5 ohms stereo loads. Unfortunately my current setup provides loads down to 2 ohms and no 1 ohm or 0.5 ohm configuration. I'll add more resistors in the future and test these amps again to find out their full output potential. I have little doubt the Orion 225HCCA will output over 500 watts but have less optimism in the Phoenix Gold MPS-2240...especially when comparing the 4 ohm mono vs. 2 ohm mono loads with this amp.

I hear ya, enough with the jibber-jabber, on with the results! See the embedded spreadsheet below or Click HERE to see the full size image:

Testing Power Output from Old School Amps

Old School friends, have you ever wondered how underrated your treasured amps are? Well, I must say I've always wanted the ability to measure actual output from my amps to show we did actually get what we paid for.

My wishes have come true with the latest 2 items I've added to my test bench....an Oscilloscope and a "dummy load" (aka "Fred Sanford") resistor bank. The o'scope is a portable model by Velleman (HPS50) and the resistor bank is one I put together based on another project I found online. See the detailed layout here:

400W Dummy Load Project

I essentially took his design and doubled it. This gives me (2) 400W loads at 4ohms or (1) 800W load at 2ohms. These resistors can handle up to 3x their rated power for short periods of time. I had originally planned on using 32 instead of 16 resistors, but then decided I could add more in another enclosure as needed. Here is a pic of my creation:

So some of you may be wondering what the resistors are used for. Basically, they are designed to handle the output power from the amps without producing any sound. This allows you to reach max output without damaging your hearing. After I did a simple test with an old Realistic speaker, there was no doubt I needed to build a Fred Sanford. Not to mention, I can safely test many different frequencies, including 1000Hz, which is not pleasing to hear at high volumes!


Next, I needed an oscilloscope to monitor the waveform from the amp. I considered many models, including desktop and portable designs. I finally settled on the Velleman HPS50 portable oscilloscope. I purchased from Kitsusa.net and it was around $230US shipped. I also considered the HPS10SE, but it did not have USB output for monitoring / capturing via PC, which I thought may be important. Another selling point for me of the Velleman o'scopes is the built-in audio measurement tools. They essentially have a built-in True RMS Volt meter and taking the AC Volts x AC Volts and dividing by the ohm load you get max output power (The Velleman does the math for you and just shows power output). The HPS50 will also let you decide between MAX power and RMS power. I decided to perform all of my tests using the RMS power measurement.

Components used in my testing include:

• 100A Audio Authority 978 13.8V Power Supply
• iPod Nano (1st Gen) with test tones - 100Hz and 1000Hz
• 1/8" to stereo RCA adapter
• 12ga Speaker Wire to Connect Amp to Dummy Load
• Windows XP laptop to monitor/capture live waveform from HPS50
• Velleman HPS50 Portable Oscilloscope
• 800W Dummy Load Resistor bank (AKA "Fred Sanford")
  

So, I bet you are curious about some of my findings....stay tuned as I'll post results very soon....

-BigD

Velleman HPS50 Portable Oscilloscope for Testing Amp Output Power

I finally got a chance to test the Velleman HPS50 today. It was pretty simple to setup, even for the o'scope novice like myself.

I don't have my dummy load resistor bank yet, but I do have a 6.5" Realistic Dual Cone car speaker I was willing to donate to the cause. I measured it's resistance to be 4.2 ohms.

I used a 100Hz test tone for my tests and calibrated the HPS50 per the instructions. First, ensure the switch on the probe is set to 10x, also check the display to ensure 10x. Then use the tip of the probe to touch the calibration point on the side of the scope. Lastly, view the waveform, and adjust the small screw on the probe until the wave form has even square waves. (I was wondering what the small, plastic screwdriver was for in the box, now I know!)

You have a few choices for measuring power output. I initially tested Peak watts, then decided RMS was a better test. In the HPS50, it is displayed as W^4Ω. You can also set the ohms (Ω) to 2, 4, 8, 16 or 32. Since my speaker measured 4Ω, I set the meter to "W^4Ω" for RMS wattage at 4 ohms. I'll eventually put together a demo video of the unit, with setting up the unit for power output being the main objective.

I already had a Rockford Fosgate Punch 4020DSM on my test bench, so I decided it would be a good first test. The "old school" amp is rated at 20 watts x 4 @ 4 ohms. My test signal was a 100Hz tone and my power source was my Audio Authority Model 978 100A 13.8V power supply.

Here are my results:

76.65 watts RMS per channel (only 1 of the 4 channels driven) @ 4ohms, 100Hz @ 13.8v. Not bad for an amp rated at 20 watts per channel! The main difference to note is I can't measure THD, so Rockford's measurement (although still way underrated) was tested at 0.1% or less THD while mine could be up to 10%. They also usually test at 1000Hz, my test was limited to 100Hz (mainly to save my eardrums!). Once I get my resistors, I'll be able to test at various frequencies.

I also had a Rockford Fosgate Punch 30HD close by and knew it would be a good test. The amp is rated at 15 watts x 2 @ 4 ohms. I measured 24.75 watts RMS (from 1 channel) @ 4ohms, 100Hz @ 13.8v.

The HPS50 will connect to a PC via USB and capture real-time data as well. I attempted to test with my Windows 7 32-bit laptop and was unable to get the o'scope to communicate with the Velleman software. From reading the forms about this unit, many others are experiencing issues as well with Windows Vista. I'll attempt to install the software on a Windows XP computer to see if I can get the device communicating for real-time capture.

So far, the Velleman HPS50 is a fun tool! More tests coming soon...I'll have my dummy load setup complete and will begin testing the output power of my old school amps. Stay tuned in...